Highly sensitive amperometric sensing of nitrite utilizing bulk-modified MnO2 decorated Graphene oxide nanocomposite screen-printed electrodes

A screen-printed amperometric sensor based on a carbon ink bulk-modified with MnO2 decorated graphene oxide (MnO2/GO-SPE) nanocomposite was investigated for its ability to serve as a sensor towards nitrite. The composite was prepared by simple ultrasonication and reflux methodology and was characterized by FT-IR spectroscopy, transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, atomic force microscopy and electrochemically using cyclic Voltammetry, chronoamperometry and differential pulse voltarnmetry techniques. The MnO2/GO-SPE Was found to exhibit an electro-catalytic activity for the electrochemical oxidation of nitrite in 0.1 M phosphate buffer solution (pH 7.4). The electrochemical oxidation of nitrite occurs at +0.55 V (Vs. Ag/AgCl) With a limit of detection (3 sigma) found to be 0.09 mu M and with two linear ranges of 0.11 mu M to 1 mu M and 1 mu M to 1000 mu M with sensitivities of 1.25 mu A mu M-1 cm(-2) and 0.005 mu A mu M-1 cm(-2) respectively. Furthermore, the MnO2/GO-SPE showed an excellent anti-interference ability towards a range of commonly encountered electroactive species and metal ions. Additionally, the fabricated MnO2/GO-SPE nitrite sensor presented an excellent selectivity, reproducibility and stability. The presented study widens the scope of applications of graphene-based nanocomposite materials for on-site monitoring of nitrite. (C) 2017 Elsevier Ltd. All rights reserved.